The field of the disclosure relates generally to gas turbine engines and, more particularly, to an attachment system for coupling components.
Military purpose gas turbine engines are known to include a front frame assembly, an upstream end of which forms an inlet flowpath. The inlet flowpath is sized to provide a predetermined airflow to a fan assembly disposed directly downstream of the front frame assembly. The fan assembly typically includes a plurality of fan blades that rotate at high speed behind the front frame assembly during engine operation. Downstream of the fan assembly is typically a core engine for combusting fuel mixed with pressurized air to produce combustion gases that produce a propulsive force for the engine when discharged.
The high speed rotation of the fan assembly directly behind the front frame assembly places significant load stresses between the inner and outer casings of the front frame assembly. The loss of a fan blade during operation of the engine, sometimes referred to as a “blade out” condition, can place a considerably greater load stress on the fan frame assembly. This load stress can increase for larger engines utilizing larger fan assemblies. Some known front frame assemblies utilize a greater quantity of struts to connect the inner and outer casings, however, additional struts impede airflow into the fan assembly, and also add weight to the engine, which reduces engine efficiency. Other known front frame assemblies add additional bolts or welded joints within the inlet flowpath to more securely attach the struts to the inner and outer casings, however, these additional attachments within the flowpath also impede airflow into the fan assembly.